A polygamist is a person who is part of a plural marriage, a union in which one person is married to more than one member of the opposite sex. Polygamy is commonly known in the United States as part of the Mormon faith.
There are multiple societies around the world that practice polygamy that include one man with multiple wives, one woman with multiple husbands and a community where everyone can marry multiple partners. The concept of polygamy was first introduced into the Mormon faith during the 1840s by Joseph Smith. Today there are sects of the Mormon faith that still practice polygamy and others who believe that God lead them to practice polygamy in the nineteenth century for religious reasons, even though they believe it against their faith now.